Robots used in industrial manufacturing applications are well known. Such robots are designed and programmed to perform specific functions repeatedly and precisely. Thus, robots are often used in such applications to perform operations, such as assembly in an assembly line setting, more efficiently, and often producing higher and more consistent quality, than such operations could be performed by humans.
Conventional industrial robots typically have one or two robotic arms. These robotic arms can have multiple segments that facilitate movement in multiple degrees of freedom (DOF). Movement of the arms may be provided by stepper or other controllable motors, typically under computer control. In other applications hydraulics or pneumatics may be used to actuate the robot arm segments.
An example of a typical industrial robot is a Selectively Compliant Articulated Robot Arm (SCARA) robot. Known SCARA robots typically operate with four or fewer degrees of freedom, i.e., these robots are designed to move along four or fewer axes of rotation.
A typical application for a conventional robotic arm of this type in an industrial setting is that of a pick-and-place type machine. Pick-and-place type machines are used for automation assembly, automation placing, printed circuit board manufacturing, integrated circuit pick and placing, and other automation jobs that contain small items, such as machining, measuring, testing, and welding. These robotic arms include an end-effector, also known as a robotic peripheral, robotic accessory, robot or robotic tool, end of arm (EOA) tooling, or end-of-arm device. The end effector may be implemented such as a robotic gripper, press tool, paint gun, blowtorch, debarring tool, arc welding gun, drills, etc. These end-effectors are typically placed at the end of the robotic arm and are used to perform the functions described above. One common end-effector is a simplified robotic version of a hand, which can grasp and carry different objects.
Some conventional industrial robots have been modified for patient positioning in a medical setting. For example, in external radio therapy, e.g., using a proton beam, the radiation beam employed is either fixed or of limited mobility. In such an application a patient may be positioned on a patient treatment table that in turn is coupled to the end of the robot arm. The robot is then precisely controlled to move the patient relative to the treatment beam to achieve the desired therapeutic exposure. Precise control is achieved in such an application by the precise positioning of the patient on the treatment table such that the exact position of the treatment area of the patient, obtained prior to therapy, is known with respect to the position of the robot arm at any point in time.
An example of a robot used in such a medical setting is described in United States Patent Application Publication No. US 2005/0234327, entitled “Robotic Arm for Patient Positioning Assembly”. This robotic patient positioning assembly includes an articulated robot arm that includes a track mount assembly to facilitate movement of a patient on a patient treatment couch (e.g., table or chair) in a three dimensional (3D) space, as well as raising and lowering the patient to high and low positions without compromising the flexibility or positioning in translational and rotational movements. The track mount assembly may be vertically mounted, for example to a vertical side of a column. This particular system features a first arm segment movably attached at a first end thereof to the track mount assembly that is attached to the vertical column, and a second arm segment, of different length from the first arm segment, moveably attached at a first end thereof to the second end of the first arm segment. The patient table is positioned at the second end of the second arm segment. The second arm segment is attached below the first arm segment, such that the patient table may be lowered as close to the floor of the treatment room as possible. Unfortunately, this arrangement provides an envelope in which the patient table may be positioned that has voids. In other words, by having the second arm below the first, the second arm runs into the track mount assembly.
This limited positioning envelope 300 is illustrated in FIG. 8. More particularly, second arm segment 302 is positioned below first arm segment 304 that is mounted to track mount assembly 306. Thus, the motion of the second arm segment 302, and typically even the first arm segment 304, is obstructed by the track mount assembly 306. Thus, the envelope 300 is created that limits the positioning of any device, typically the patient table, mounted to the end of the robotic arm. These limitations may be referred to as “dead spots” illustrated generally at 308.
Further, as illustrated in U.S. Patent Application Publication 2007/0230660 published Oct. 4, 2007 entitled “Medical Radiotherapy Assembly,” to Herrmann, a robotic patient positioner system is illustrated. However, in this robotic system the vertical movement is not provided in a direct perpendicular path relative the floor. Instead, two robotic arms must be moved relative to one another to get a variation in the vertical position of the patient. Further, due to the lack of a direct linear vertical positioning component, the envelope for positioning the patient is limited. This arrangement provides for numerous dead spots within the envelope for positioning the patient relative to the particle emitter therefore limiting the effectiveness of the patient positioner system.
The use of robots for patient positioning in medical treatment and similar settings poses both opportunities for increased patient treatment efficiency (and therefore lower cost) and effectiveness, and challenges for patient and medical personnel safety. Radiotherapy operations, such as proton beam treatment, can be very expensive, both in the capital cost involved in setting up such a facility and the operational costs associated with facility operations. To the extent that patient positioning system robots can be used to reduce overall treatment facility capital costs and/or increase patient throughput, that is, reduce the time required for each patient to occupy the facility to receive the desired treatment, the per patient treatment costs can be reduced. However, such increased efficiency can not be obtained at the cost of reduced treatment effectiveness or of reduced safety to the patient or to medical personnel providing such treatment. What is desired, therefore, is an improved patient positioning system that takes advantage of robot technology to the greatest extent to improve the efficiency (reduce the cost of) and effectiveness of patient radio therapy and other treatments while improving patient and operator safety as well.